1. Field of the Invention
The present invention relates to a digital X-ray detecting device, and particularly to a digital X-ray detecting panel and a method for manufacturing the same.
2. Description of the Related Art
Digital X-ray detecting devices are widely used in a lot of fields because of nondestructive detection characteristic. A conventional digital X-ray detecting device generally includes a digital X-ray detecting panel and a driving circuit electrically connected to the digital X-ray detecting panel. The digital X-ray detecting panel is used for transforming optical signals into electric signals and sending the electric signals to the driving circuit, and thereby obtaining an image information corresponding to the optical signals. The digital X-ray detecting panel generally includes a wavelength transforming layer and a photodetector array substrate. The wavelength transforming layer (e.g. scintillator) is used for transforming X-ray into visible light. The photodetector array substrate is disposed under the wavelength transforming layer and is used for transforming the visible light into electric signals. The photodetector array substrate generally includes a substrate and a number of photodetectors disposed on the substrate and arranged in an array.
FIG. 1 is a schematic view of a photodetector of a conventional digital X-ray panel. Referring to FIG. 1, each photodetector 100 of a conventional X-ray panel is disposed on the substrate 105. The photodetector 100 includes an amorphous silicon thin film transistor (a-Si TFT) 110 and a photodiode 120 electrically connected to the amorphous silicon thin film transistor 110. The amorphous silicon thin film transistor 110 includes a first metal layer 111, an insulating layer 112, an amorphous silicon layer 113, an ohmic contacting layer 114 and a second metal layer 115 formed on the substrate 105 in order.
The amorphous silicon thin film transistor 110 is electrically connected to the corresponding photodiode 120 through the second metal layer 115. However, it is well known that the amorphous silicon material has a sensitive property. After the X-ray is transformed into the visible light having a wavelength of 550 nanometers by the wavelength transforming layer 130, the visible light will cause to produce a photocurrent in the amorphous silicon layer 113 of the amorphous silicon thin film transistor 110. Thus, an electric leakage is caused in the amorphous silicon thin film transistor 110, so the digital X-ray detecting panel has a poor detecting accuracy. In order to solve this problem, a metal layer 140 is generally formed above the amorphous silicon thin film transistor 110. The metal layer 140 is used for blocking the visible light so as to prevent the visible light illuminating the amorphous silicon thin film transistor 110.
Because of the formation of the metal layer 140, the process of manufacturing the conventional digital X-ray detecting panel becomes more complex, and thereby increasing the cost of the conventional digital X-ray detecting panel and decreasing the manufacturing efficiency of the conventional digital X-ray detecting panel.
In addition, the amorphous silicon layer 113 of the amorphous silicon thin film transistor 110 of the conventional digital X-ray detecting panel is generally formed by a plasma enhanced chemical vapor deposition (PECVD) process. Because a processing temperature of the PECVD process is high (about 380 Celsius degrees), the high processing temperature when forming the amorphous silicon layer 113 may affect other materials of the conventional digital X-ray detecting panel, and thereby reducing the quality of the conventional digital X-ray detecting panel.